Torn Mesh when transparent?
This problematic behaviour can't be changed.

But since it is only a viewport problem, it won't affect the render. The backface and the frontfaces are both visible and don't get rendered properly. There are two temporary options.


Don't show transparency in the viewport. Toggle off show transparency under Properties > Object. To preview the effect you'll have to use the render preview &#8679; ShiftZ.

Enable backface culling, that way the backfaces don't get involved in the viewport render. Transparent frontfaces are combined correctly.